European priorities for research to support legislation in the area of food contact materials and articles

Variability of organophosphorus insecticide residues in large size crops grown in commercial farms in Brazil

Field trials were conducted in commercial agricultural areas in Brazil to determine the variability of residues of parathion methyl, diazinon and methidathion in individual units of large crops treated twice with a mixture of the three pesticides. Over 120 random samples were collected, extracted with ethyl acetate and residues determined by GC/FPD. The recoveries and their coefficient of variation were, in general, within the acceptable levels during sample analyses. Residues in papaya and mango were not affected by the position of the fruits in the plant, apparently more or less exposed to the pesticides. Variability factor ?, defined as the 97.5th percentile divided by the mean of residues in all samples taken from a field ranged from 2.0-2.6. The variability of residues within the plant contributed to about 34-61% of the field variability. The results found in this study support the variability factor of 3 adopted by the FAO/WHO for the deterministic estimation of dietary acute intake of pesticides.

[Migration of di(2-ethylhexyl) phthalate from polyvinyl chloride tubes used in preparation of foods]

Three samples of polyvinyl chloride products for food use were examined for di(2-ethylhexyl) phthalate (DEHP) migration levels under the conditions described in the Japanese Food Sanitation Law. These samples were two kinds of tubes and one stretched film, containing 12 to 41% DEHP by weight. DEHP migration levels from them were very low, all below 0.1 ppm, into 3 kinds of food simulant; water, 4% acetic acid and 20% ethanol. However, high levels of DEHP migrated into n-heptane, 12 ppm from the stretched film sample and more than 800 ppm from the tube samples. Migration from the 2 tubes was higher than 150 ppm, the limit of residues after evaporation in containers and wraps. Though the limit of residues after evaporation is not set for equipment used in the preparation of foods, the tested tubes were considered to be unsuitable for uses in which they come into direct contact with oils, fats or oily foods.

Creation of on-line solutions in support of the dissemination of legislative and analytical information on food-contact materials

To facilitate access to European Commission (EC) documentation and provide a public service resource of relevant information an Internet site dedicated to food-contact materials was created (http://cpf.jrc.it/webpack/) in 1998. The site contains legislative information in downloadable format, information on contacts for authorities and organizations in the field of food-contact materials, as well as information on methods for overall and specific migration. A satellite site (http://cpf.jrc.it/smt/) is dedicated to physicochemical and spectral information (FT-IR, GC-MS, NMR) as well as analytical methods on an increasing number of regulated substances. Many of these, as well as substances submitted for evaluation, are held in a centralized databank at the JRC in Ispra and aliquots can be made available to the public upon request. The site also recently expanded to provide an incentive for analytical networking between institutions by including information pages on current EC-funded and national projects and conference announcements.

Analyses of volatile transformation products from additives in gamma-irradiated polyethylene packaging

Thermal desorption, followed by gas chromatography (GC) with mass spectrometry (MS) detection, has been found to allow the rapid identification of volatile products resulting from the gamma-irradiation of stabilized, high density polyethylene packaging and pure stabilizers. The stabilizers were tris(2,4-di-tert.butylphenyl) phosphite, octadecyl beta-(2,6-di-tert.butylphenol)-propionate and 2,4-di-tert.butylphenol, the latter resulting from phosphite hydrolysis. Thermal desorption indicated the formation and release of tert.butylbenzenes, such as 1,3-di-tert.butylbenzene upon gamma-irradiation of the HDPE. From a comparison of the products from gamma-irradiation of additive-free polyethylene, of various pure stabilizers and of related compounds, the tert.butylbenzenes were confirmed to result from the irradiation of the phosphite stabilizer and its phosphate conversion product. Thermal desorption off-line, in which volatiles released by a sample are trapped in sorbents for subsequent desorption in the heated GC inlet, is found to be a fast, extremely sensitive method that can be used to guide and supplement analyses of compounds extracted by foodstuffs.

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (1H-NMR) and GC-MS. NMR detected the presence of cyanoisopropyl radical residues in the plastic at 470-3400 mg/kg whereas GC-MS detected TMSN at only 65-540 mg/kg in the samples. It is concluded that the bulk of cyanoisopropyl residues detected by NMR were either polymer-bound or were the products of side-reactions of the initiator radical. The migration of TMSN itself into the food simulants 3% aqueous acetic acid, 15% aqueous ethanol, and olive oil, at 40 degrees C for 10 days, was measured using GC-MS. Migration was very low with < 1 microg/kg released from a finished article (a drinking straw) and < 5 microg/kg from resin pellets. The overall conclusions from this work are that organic residues from aids to polymerization are generally found at reassuringly low levels in plastics intended for food contact and their potential for migration to foods is correspondingly low.